Not from Mac to Windows, or vice versa, but rather in a more important way. I’ve switched from the fabulous LaunchBar to the very new and slick Quicksilver. Between those two and Butler, if they’re mentioned in the same breath to a large crowd, you can expect some blood to be spilled. You’d see a religious war that would rival the Mac OS X text editor war (BBEdit vs. SubEthaEdit vs. TextMate etc.).
I was a huge LaunchBar fan. Soon after I registered it, I started hearing things about Quicksilver. Being free and open-source, I thought I’d give it a try. I was less than impressed. I didn’t see any compelling features and the results I got weren’t nearly as good as LaunchBar’s. I deleted it and ran back to LaunchBar.
Recently, I started reading 43 Folders, which has frequent articles on it. Either I missed a lot, or Quicksilver gained a lot of functionality since I last tried it. I’m going to lean to the latter. At any rate, until LaunchBar gains the ability to perform the breadth of actions that Quicksilver can (which is extensible), I’m switching.